#include<stdio.h>
void main()
{
    float x,y;
    scanf("%f",&x);
    if(x<=-10){
        y = x+10;
    }
    else if(x<=0){
        y = x+5;
    }
    else if(x<=10){
        y = x-5;
    }
    else{
        y = x-10;
    }
    printf("y = %f\n",y);
}